Sorting apparatus and detection method

ABSTRACT

A sorting apparatus comprises a conveyance path, a first storage section, a detection section, a first roller and a control section. The conveyance path conveys a sheet. The first storage section stores the sheet conveyed through the conveyance path. The detection section detects whether or not the sheet conveyed in the conveyance path is in the detection target area of the conveyance path. The first roller is located at the downstream side of the detection target area of the detection section in a conveyance direction of the conveyance path, and rotates to convey the sheet in the conveyance path towards the first storage section. The control section reversely rotates the first roller when the conveyance path is recovered from a stop state so that the sheet in the conveyance path is moved for a distance from the first roller to the detection target area of the detection section.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2013-093544, filed Apr. 26, 2013, the entire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate to a technology for determining whether or not there are sheets in an apparatus.

BACKGROUND

In an apparatus in which a sheet is conveyed, such as an image forming apparatus for forming an image on a sheet, an erasing apparatus for erasing the image formed on a sheet and the like, it is needed to check whether or not there are sheets in the apparatus. The check on whether or not there are sheets in an apparatus is carried out by a plurality of detection sensors arranged along a conveyance path inside the apparatus to specify the position of a conveyed sheet during the operation process of the apparatus, or to confirm whether or not there are sheets left in the apparatus when the apparatus resumes from a fault such as paper jam and the like or when the apparatus is powered on.

In addition, there is an image forming apparatus which switches between trays serving as discharge destinations according to the material or size of a sheet, and an erasing apparatus which distinguishes between reusable sheets and not-reusable sheets according to a residual image condition of a sheet subjected to an erasing processing and then switches between trays serving as discharge destinations.

The following technology is disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating an example of the hardware constitution of an erasing apparatus according to an embodiment;

FIG. 2 is a diagram illustrating the specific constitution of a discharging section according to the embodiment;

FIG. 3 is a block diagram illustrating the constitution of the erasing apparatus according to the embodiment;

FIG. 4 is a flowchart illustrating an example of the overall operation of the erasing apparatus according to the embodiment;

FIG. 5 is a flowchart illustrating an example of an operation of detecting a sheet held by a discharging roller with a sensor according to the embodiment;

FIG. 6 is a flowchart illustrating an example of an operation of uniformly discharging residual sheets to a predefined tray; and

FIG. 7 is a flowchart illustrating an example of an operation of discharging residual sheets according to a determination result.

DETAILED DESCRIPTION

In accordance with one embodiment, a sorting apparatus comprises a conveyance path, a first storage section, a detection section, a first roller and a control section. The conveyance path conveys a sheet. The first storage section stores the sheet conveyed through the conveyance path. The detection section detects whether or not the sheet conveyed in the conveyance path is in the detection target area of the conveyance path. The first roller, which is a roller located at the downstream side of the detection target area of the detection section in a conveyance direction of the conveyance path, rotates to convey the sheet in the conveyance path towards the first storage section. The control section rotates, when the conveyance path is recovered from a stop state, the first roller in a direction reverse to the direction of the rotation mentioned above so that the sheet in the conveyance path is moved for a distance from the position of the first roller to the detection target area of the detection section.

When powered on or recovered from a faulted state, the apparatus disclosed herein reversely drives the motor of the discharging section for a certain amount until a sheet is conveyed to the position of the detection sensor (referred to as detection target area) on the conveyance path, thereby determining whether or not there are residual sheets through a sensor check. If there are residual sheets, the apparatus described herein conveys the sheets to a position where the sheets can be removed.

An apparatus is considered in which as a residual sheet removing method, a conveyance roller is driven forward (in a rotation direction along which a sheet is discharged to a discharging tray) no matter whether there are sheets or not, and if there are residual sheets inside the apparatus, the residual sheets are discharged to a discharging tray under the rotation. However, in this method, in a case where it is needed to change a discharging tray according to the size or state of a sheet, if the sheets are directly discharged without considering the size or state thereof, the sheets of different sizes or reusable sheets and not-reusable sheets are mixed together.

In the application of the embodiment described below, the user can take out a sheet, confirm the residual image condition or the size of the sheet and then place the sheet in a regular tray.

By taking an erasing apparatus as an example, embodiments of the present invention are described below with reference to the accompanying drawings. In addition, although a sheet is described below as a paper medium in the following description, the present invention is not limited to this.

FIG. 1 is a schematic diagram illustrating the constitution of an erasing apparatus. An erasing apparatus 100 carries out an erasing processing (erasing processing) of erasing an image formed on an sheet with a color erasable material (erasable material) such as a color erasable toner or color erasable ink. The color erasable material contains a color generation compound, a color developing agent and an erasing agent. The color generation compound is, for example, leuco dye. The color developing agent is, for example, phenols. The erasing agent is, for example, a material which, when heated, is dissolved with the color generation compound and has no affinity with the color developing agent. The color erasable material generates a color through the interaction of the color generation compound and the color developing agent and is decolorized after being heated to a temperature higher than an erasing temperature to eliminate the interaction of the color generation compound and the color developing agent. The color erasable material is hereinafter referred to as a recording material, as needed.

The erasing apparatus 100 comprises a sheet feed tray 102, a sheet feed component 104, a reading section 106, an erasing section 108, a discharging section 500, a first conveyance path 118, a second conveyance path 120, a third conveyance path 122, a first branching component 124, a display operation section 128 and an opening/closing cover 131. The discharging section 500 comprises a first tray 110, a second tray 112, discharging rollers 114 and 116, a second branching component 126 and a detection sensor 129. In FIG. 1, the first conveyance path 118 is represented by a solid arrow, the second conveyance path 120 is represented by a dotted arrow, and the third conveyance path 122 is represented by a one dotted line arrow. Starting points of these arrows are at the upstream sides of the conveyance paths, and the rears (the arrowheads) of those arrows are at the downstream sides of the conveyance paths.

The sheet feed tray 102 holds reusable sheets of different sizes (e.g. A4, A3, and B5). The sheet held on the sheet feed tray 102 is a sheet on which an image is formed with a recording medium which is erased when the recording medium is heated to a temperature above a given temperature. The sheet feed component 104, which comprises a pickup roller, a sheet feed roller and a separation roller arranged opposite to the sheet feed roller, feeds, one by one, the sheets on the sheet feed tray 102 to the first conveyance path 118 inside the erasing apparatus 100. Further, the sheet feed tray 102 detects whether or not there are sheets thereon.

The first conveyance path 118 conveys the sheet fed from the sheet feed tray 102 to the reading section 106, and then to the first tray 110.

The reading section 106 is located at the downstream side of the sheet feed tray 102 in the sheet conveyance direction and arranged along the first conveyance path 118. The reading section 106 is provided with a reading unit such as a CCD (Charge Coupled Device) scanner or a CMOS sensor. In the present embodiment, the reading section 106 reads the images on the first and second sides of a conveyed sheet. That is, the reading section 106 including two reading units arranged along the first conveyance path 118 across the conveyance path can read images on two sides of a conveyed sheet. The image read by the reading section 106 is stored in a memory 210 or a storage section 205 which will be described later. For example, the image on the sheet read by the reading section 106 before the erasing processing is converted into digital data and stored in the storage section 205 so that image data is available later when the data of the color erased image is needed. Further, the control section 200 described later determines whether or not a sheet is a color erasable sheet or a reusable sheet based on the image read by the reading section 106.

The first branching component 124 is arranged at the downstream side of the reading section 106 as a switching section. The first branching component 124 switches between sheet conveyance directions. The first branching component 124 conveys a sheet conveyed in the first conveyance path 118 to the second conveyance path 120 or the first tray 110. The second conveyance path 120 is a conveyance path branching off from the first conveyance path 118 at the first branching component 124 between the reading section 106 and the first tray 110 to convey a sheet to the erasing section 108. Further, the second conveyance path 120 merges with the first conveyance path 118 at a mergence point 121 at the upstream side of the reading section 106 in the sheet conveyance direction. Thus, the second conveyance path 120 is capable of conveying the sheet conveyed from the reading section 106 to the reading section 106 again via the erasing section 108. In other words, the erasing apparatus 100 can control the first branching component 124 to orderly convey the sheet fed from the sheet feed component 104 to the reading section 106, the erasing section 108 and the reading section 106.

The second branching component 126 located at the downstream side of the first branching component 124 guides the sheet conveyed from the first branching component 124 to the first tray 110 or the third conveyance path 122 which conveys the sheet to the second tray 112.

The erasing section 108 erases the image formed on the conveyed sheet. For example, the erasing section 108 heats, while in contact with, the conveyed sheet to a given erasing temperature, thereby erasing the image formed on the sheet with a recording material.

The erasing unit 108 comprises two heat sources for erasing the color of the first and second sides of a sheet. The heat sources, both of which have a heat roller for generating heat when powered on, are arranged along the sheet conveyance direction of the second conveyance path 120. One of the heat rollers contacts with the first side of a sheet to heat the first side while the other one contacts with the second side of the sheet to heat the second side. In this way, the erasing section 108 erases the images on two sides of a conveyed sheet at one time.

The display operation section 128 arranged on the upper portion of the main body of the erasing apparatus 100 comprises a panel type display section and an operation section including a touch panel laminated on the display section and various operation keys. The operation keys include, for example, a numeric keypad. By operating the display operation section 128, a user instructs a functional operation of the erasing apparatus 100 such as the start of an erasing processing or the reading of an image on a sheet to be erased. The display operation section 128 displays the set information, the operation status and the log information of the erasing apparatus 100 or a message provided to the user.

The discharging rollers 114 and 116 discharge sheets to the first tray 110 and the second tray 112 which are vertically arranged on the lower portion of the main body. The first tray 110 stacks reusable sheets the image on which is erased. The second tray 112 stacks sheets which are determined to be not-reusable. Further, the sheets to be stacked in the first tray 110 and the second tray 112 can be exchanged. The setting on the type of the sheet held in each tray, that is, the conveyance destination of a sheet may be carried out through the display operation section 128. The second branching component 126 switches between conveyance paths to guide a conveyed sheet to the first tray 110 or the third conveyance path 122 according to the setting.

The opening/closing cover 131, which is arranged on the side wall of the housing of the erasing apparatus 100, covers the inside of the erasing apparatus 100 when closed, or exposes a part of the first conveyance path 118 outside the main body of the erasing apparatus 100 when opened. When there is a sheet nearby the opening/closing cover 131, the user can see the sheet when the opening/closing cover 131 is opened. Further, if there are sheets sopping nearby the opening/closing cover 131, the user can open the opening/closing cover 131 to take out the sheets. Although only the opening/closing cover 131 is shown in this example, such a kind of opening/closing covers are arranged at a required position.

FIG. 2 is a diagram illustrating the specific constitution of the discharging section 500. The discharging section 500 comprises the aforementioned second branching component 126 and a detection sensor 129 for detecting whether or not there is a sheet conveyed in the first conveyance path 118. In the first conveyance path 118, the detection sensor 129 is located at the downstream side of the second branching component 126 in the conveyance direction. The detection sensor 129 outputs an OFF signal (or outputs no signal) when there are no sheets in the detection target area, and outputs an ON signal when the front end of a sheet in the conveyance direction enters the detection target area. Further, the detection sensor 129 outputs an OFF signal when the rear end of a sheet in the conveyance direction leaves the detection target area. That is, the detection sensor 129 outputs an ON signal when there is a sheet in the detection target area and an OFF signal when there are no sheets in the detection target area.

The aforementioned discharging roller 114, which is arranged at the downstream side of the detection sensor 129 in the conveyance direction of the first conveyance path 118, consists of a pair of rollers which are located at the rear end of the first conveyance path 118 and arranged opposite to each other across the first conveyance path 118. The discharging roller 114 rotates forward to discharge a sheet from the first conveyance path 118.

The first tray 110 has a vertical alignment roller 135 for aligning the sheets held in the first tray 110 in a conveyance direction. With the vertical alignment roller 135 and a stopper (not shown) in the first tray 110, sheets are held in the first tray 110 in an aligned state.

Operations of the discharging section 500 are described. The sheet conveyed by the first conveyance path 118 is detected when entering the detection target area of the detection sensor 129 and is undetected after the rear end of the sheet leaves the detection target area. When the output signal of the detection sensor 129 is switched from ON (sheet detected) to OFF (sheet undetected), the discharging roller 114 stops rotating temporarily. In this way, the discharging roller 114 holds the part of the sheet close to the rear end of the sheet. Meanwhile, a determination is made to discharge the sheet to which one of the first tray 110 and the second tray 112. If the determination result instructs to discharge the sheet to the first tray 110, the discharging roller 114 recovers from the stop state and continues to rotate forward, thereby discharging the held sheet to the first tray 110. On the other hand, if the determination result instructs to discharge the sheet to the second tray 112, the second branching component 126 switches the path so that the sheet held by the discharging roller 114 enters into the third conveyance path 122. Then after the path switching, the discharging roller 114 rotates backward to return the held sheet to the conveyance path (switchback operation). In this way, the sheet held by the discharging roller 114 enters the third conveyance path 122 and then discharged to the second tray 112. The operation is controlled by the control section 200 described later.

Further, the first tray 110 and the second tray 112 can slide in the direction of Y-axis shown in FIG. 1 and FIG. 2. The user pulls the first tray 110 or the second tray 112 towards the nearer side of the Y axis to expose the tray. Then, the user can take out the sheets held on each tray in this state.

FIG. 3 is a block diagram illustrating the hardware constitution of the erasing apparatus 100. The erasing apparatus 100 comprises a control section 200, a sheet feed section 201, an erasing section 108, a reading section 106, a conveyance section 203, a display operation section 128, a storage section 205 and a discharging section 500. The sheet feed section 201, which is a section for holding the sheets to be processed and feed the sheet to the main body of the erasing apparatus 100, comprises a sheet feed tray 102, a detection sensor 103 and a sheet feed component 104. The conveyance section 203, which is a section for conveying a sheet to each unit, comprises a first conveyance path 118, a second conveyance path 120, a third conveyance path 122 as well as a plurality of roller pairs located in each conveyance path and a motor (not shown) for controlling the rotation of the roller pairs. The storage section 205 is an HDD (Hard Disk Drive) for storing user data or set data used by a system in a nonvolatile manner. The storage section 205 can also permanently store the image data read by the reading section 106.

The control section 200, which is a section for uniformly controlling each piece of hardware inside the erasing apparatus 100, comprises a processor 209, a memory 210 and an I/O (Input/Output) controller 211. The processor 209 is, for example, a CPU (Central Processing Unit) or an MPU (Micro Processing Unit) which executes the programs pre-stored in the memory 210 or the storage section 205, thereby giving an instruction to each piece of hardware. The memory 210, which is, for example, a semiconductor memory, has a ROM (Read Only Memory) for storing various control programs and a RAM (Random Access Memory) for providing a temporary working area for the processor 209. The memory 210 stores, for example, the print rate of a sheet serving as a threshold value for determining whether or not the sheet is reusable and a concentration threshold value for determining whether or not an image is erased. The memory 210 can also temporarily store the image read by the reading section 106. Each unit of the erasing apparatus 100 is connected with each other through the I/O controller 211 and sends or receives an instruction signal and the like.

A motor 501 in the discharging section 500 shown in FIG. 3 is a motor for directly controlling the rotation driving or the rotation speed of the discharging roller 114 and the vertical alignment roller 135 according to an instruction from the control section 200.

The sections inside the discharging section 500 except for the erasing section 108, the reading section 106, the display operation section 128 and the motor 501 are the same with those described above and are therefore not described herein repeatedly.

The erasing apparatus 100 can execute, for example, a reading processing, an erasing processing, a sorting processing and a prior sorting processing. The control section 200 of the erasing apparatus 100 controls the reading section 106, the erasing section 108 and the other sections according to a set processing. The reading processing, the erasing processing, the sorting processing and the prior sorting processing can be executed separately or in a combination manner.

The reading processing refers to a processing of permanently storing the image read by the reading section 106 in the storage section 210. The erasing processing refers to a processing of erasing the image on a sheet by the erasing section 108.

The sorting processing refers to a processing in which the control section 200 determines whether or not a sheet is reusable based on the image read by the reading section 106. In the sorting processing, the control section 200 determines, with a threshold value, whether or not there is an image on a sheet according to the data read by the reading section 106 and determines the sheet to be not-reusable if there is an image on the sheet. For example, if there is a residual image left on a read sheet subjected to an erasing processing by the erasing section 108, the control section 200 determines that the sheet is not-reusable as there is an image left from the erasing processing. Further, in the sorting processing, the control section 200 determines a crumple depth or determines whether or not there is a fold or rip based on the data read by the reading section 106. If the crumple depth is greater than a given value or if there is a fold, rip or hole, the erasing apparatus 100 determines that the sheet is not-reusable. Additionally, the sorting processing can also be executed separately while the erasing processing is not executed. In this case, a sheet subjected to an erasing processing is held on the sheet feed tray 102 and successively conveyed to the first conveyance path 118 according to an instruction from the user. The control section 200 determines whether or not the sheet is reusable according to the image data read by the reading section 106 and discharges the sheet to the first tray 110 or the second tray 112 according to the result of the determination.

The prior sorting processing refers to a processing of determining the print rate of the image on a sheet according to the data read by the reading section 106 before an erasing processing. If the print rate is above a given value, then it is deemed that the image will be left on the sheet even if the sheet is subjected to an erasing processing, the control section 200 determines that the sheet is not-reusable without executing an erasing processing. The control section 200 discharges the sheet determined to not-reusable to the second tray 112. Alternatively, the control section 200 may also determine whether or not the data of the image on the sheet read by the reading section 106 contains confidential data or other data which is forbidden to be erased. If so, the control section 200 conveys the sheet to the second tray 112.

A combination of the aforementioned processing can be selected through the display operation section 128 of the erasing apparatus 100. Buttons are prepared for each of the aforementioned processing on the display operation section 128. The user presses one or a combination of more than one of the buttons to store the values of the processing selection in the storage section 205 or the memory 210 as flag data. The control section 200 acquires the flag data from the storage section 205 or the memory 210 when a ‘Start’ button is pressed and determines the existence of the execution of each processing according to the flag data.

The overall operation of the erasing apparatus 100 is described with reference to FIG. 4. It is exemplified in the example shown in FIG. 4 that the aforementioned reading processing, erasing processing and sorting processing is carried out.

The sheet feed section 201 feeds, one by one, the held sheets to the main body of the erasing processing 100 according to an instruction from the control section 200 (ACT001). The fed sheet is conveyed to the first conveyance path 118 (ACT002), and the reading section 106 reads two sides of the sheet (ACT003). The control section 200 permanently stores the read image in the storage section 205.

The read sheet is conveyed to the second conveyance path 120 through the path switching of the first branching component 124 (ACT004). The erasing section 108 erases the images (erases the images) on two sides of the sheet conveyed from the second conveyance path 120 (ACT005). The sheet subjected to the erasing processing is conveyed to the first conveyance path 118 again at the mergence point 121 (ACT006), and the reading section 106 reads two sides of the sheet again (ACT007). The read sheet is conveyed in the first conveyance path 118 as it is, and then temporarily held by the discharging roller 114, as stated above.

The control section 200 analyzes the image data read in ACT007 (the analysis method can be understood by dereference to the aforementioned sorting processing) and determines whether or not the sheet is reusable (ACT008). The control section 200, after determining the sheet to be reusable (YES in ACT008), instructs the motor 501 to rotate the discharging roller 114 forward. In this way, the held sheet is discharged to the first tray (ACT009). On the other hand, the control section 200, after determining the sheet to be not-reusable (NO in ACT008), carries out a path switching using the second branching component 126 and then carries out a control to rotate the motor 501 reversely to rotate the discharging roller 114 backward. In this way, the sheet held by the discharging roller 114 is discharged to the second tray 112 via the third conveyance path 122 (ACT010).

As stated above, the sheet stops temporarily at the position where the sheet leaves the detection target area of the detection sensor 129. The control section 200 analyzes the read image and determines whether or not the sheet is reusable. However, in a case where image determination takes some time, the sheet is stopped at the stop position (a position where the discharging rollers 114 are contacted with each other or meshed with each other) to wait for the result of the discharge destination tray. In this state in which the rear end of the sheet is held at the stop position, the sheet cannot be detected by the detection sensor 129, moreover, in this state, the existence of the sheet cannot be detected when, for example, the apparatus 100 is started again after being powered off. Similarly, the existence of sheets cannot be determined when the apparatus is started again, even if a fault occurs when the sheet is at the stop position.

Further, in a case where the result of the determination on the reusability of a sheet is stored in the volatile storage area of the memory 210, the information of the determination result is cleared when the erasing apparatus 100 is powered off. In this case, when the erasing apparatus 100 is powered on again, the discharge destination tray of the sheet is unknown.

Further, if the first tray 110 is pulled out by the user along the Y-axis direction (refer to FIG. 1 and FIG. 2) in a state in which the rear end of a sheet is held by the discharging roller 114, the sheet may be ripped. Thus, it is needed to inform the user of the existence of sheets in the discharging section 500. If a sensor is arranged at the downstream side of the discharging roller 114 so as to solve the problem above, the cost of the apparatus may be increased.

In the erasing apparatus 100 described herein, the discharging roller 114 is rotated reversely when the erasing apparatus 100 is powered on or recovered from a faulted state so as to reversely convey a sheet, if the sheet exists, to the detection target area of the detection sensor 129. In this way, the detection sensor 129 can detect the existence of a residual sheet. The control section 500 drives the motor 501 such that the sheet held by the discharging roller 114 is conveyed backwards for a distance longer than the distance from the discharging roller 114 to the detection target area of the detection sensor 129. If the detection sensor 129 still cannot detect the sheet (OFF signal) even if the motor 500 is rotated for a given amount, it is determined that there are no sheets in the discharging section 500. On the other hand, if the detection sensor 129 outputs an ON signal, the reverse rotation driving is continued to convey the sheet to a position where the user can carryout a removing operation, that is, a position where the user can take out the sheet from the opening/closing cover 131. The user is informed of the existence of a sheet in the discharging section 500 when the conveyance is completed and the discharging roller 114 stops rotating reversely.

FIG. 5 is flowchart illustrating the control. Apart from a case where the erasing apparatus 100 is powered on, the control is also carried out in a case where the detection sensor 129 is recovered from a power-saving mode where the detection sensor 129 is powered off or when the erasing apparatus 100 is recovered from a faulted state such as paper jam, more specifically, when the opened cover (other covers in addition to the opening/closing cover 131) on the outer wall of the apparatus is closed.

Further, the following description is given by using the distances meeting the following condition: X1<X2<X3<X4 (unit: mm). Herein, X1 is the distance between the holding position of the discharging roller 114 (the position where discharging rollers 114 are contacted with or meshed with each other, like the stop position) and the detection sensor 129, X2 is the double of X1. X4 is the distance between the detection sensor 129 and a device located at the upstream side of the detection sensor 129, and X3 is the distance from the detection sensor 129 within which the sheet does not reach the aforementioned device.

The control section 200 drives the motor to rotate reversely (ACT101). In this way, the discharging roller 114 rotates reversely. Additionally, the control described in ACT101 is carried out no matter whether or not a job is being executed.

The control section 200 determines whether or not an ON signal is output from the detection sensor 129 (ACT102). In a case where a sheet is held, the control section 200 controls the motor to rotate for a certain amount so that the sheet is reversely conveyed for X2 mm in the first conveyance path 118 (Loop of NO in ACT103), and whether or not an ON signal is output from the detection sensor 129 is determined every time the aforementioned control is carried out (ACT102). In this example, considering the slide (slip) between a sheet and the discharging roller 114, the sheet is moved for X2 mm, which is a multiple of X1 mm. Further, in this example, the multiple is set to 2, however, the multiple can be any number as long as the sheet can be reversely conveyed at least to the detection target area of the detection sensor 129.

If the detection sensor does not output an ON signal even if the discharging roller 114 is reversely rotated for X2=(NO in ACT102, YES in ACT103), it is determined that there are no sheets in the discharging section 500, the control section 200 stops reversal rotation driving of motor 501 (ACT 104), then the processing is ended. The operations following ACT104 are prior operations.

On the other hand, if the detection sensor 129 detects a sheet and outputs an ON signal before the sheet is conveyed for X2 mm (NO in ACT 103, YES in ACT102), then there are residual sheets at the discharging roller 114. In this case, the control section 200 controls the drive of the motor 501 until the sheet is further conveyed in the direction reverse to the conveyance direction and conveyed for X3 mm away from the detection sensor 129 in the upstream direction (Loop of NO in ACT103). In this example, a charge removing brush (a device by which a sheet won't be stuck when conveyed forward and will be stuck when conveyed reversely) is arranged at an upstream position of the detection sensor 129 (the position X4 mm away from the detection sensor 129), and the control section 200 controls to stop the residual sheet at an upstream position X3 mm away from the detection sensor 129 so as not to convey the residual sheet to the device (the charge removing brush). Further, the upstream position X3 mm away from the detection sensor 129 is a position where a sheet can be taken away by the user when the opening/closing cover 131 is opened.

After the sheet is conveyed for X3 mm (YES in ACT105), the control section 200 stops driving the motor 501 to rotate reversely (ACT106) and displays a message indicating that there are residual sheets on the display operation section n128 (ACT107). If the user removes the residual sheets according to the message while the discharging roller 114 is operating, there is a risk that the machine is damaged. Further, the touch of the fingers of the user with the rotating discharging roller 114 may cause injury. Thus, in the present embodiment, if there are residual sheets, a message indicating the existence of the residual sheets is displayed after the discharging roller 114 is completely stopped.

Further, as the user may touch the roller when the motor 501 is driven with the first tray 110 opened, the operations shown in the flowchart in FIG. 5 are not carried out when the first tray 110 is opened.

Further, if the first tray 110 is opened when there is a sheet at the stop position, the sheet is clamped between the housing of the first tray 110 and the housing of the main body of the apparatus 100, and if the motor 501 is driven in this state, the normally held sheets may be disorganized and the devices such as the vertical alignment roller 135 may be damaged. Thus, when the first tray 110 is opened, the control is not carried out when the cover is opened or closed for the purpose of clearing a paper jam. Information indicating that the first tray 110 is opened is initialized when a job is normally started again.

In a practical example of the flowchart shown in FIG. 5, a residual sheet, if exists, is conveyed to a user reachable position to be manually removed by the user. After taking out the sheet, the user can determine the size of the sheet or determine whether or not the residual sheet is reusable and places the sheet on a regular tray. In this way, the sheet can be placed on a regular tray corresponding to the type or use purpose thereof.

Further, even in a case of sorting sheets according to reusability, it is preferred to regularly distribute reusable sheets and not-reusable sheets to each tray; an application involving no strict manual sheet sorting is also considered. In this case, residual sheets, if exist, may be conveyed to a predefined tray, for example, the second tray 112 for holding not-reusable sheets. Such a control is described below with reference to the flowchart in FIG. 6. In addition, identical operations shown in FIG. 5 and FIG. 6, as denoted by identical reference numbers, are not described in FIG. 6 again. If the detection sensor outputs an ON signal in ACT 102 (YES in ACT102), the control section 200 switches the second branching component 126 (ACT111) to guide the residual sheet to the third conveyance path 122 (ACT112). Further, a message indicating that the residual sheet is conveyed to the second tray 112 is given (ACT113).

The practical example (refer to FIG. 5) in which a determination is made by the user and the example (refer to FIG. 6) in which the residual sheet is conveyed to the predefined tray in spite of the state of the sheet are effective when the erasing apparatus 100 is recovered from a powered off state and the result of the determination is unclear. On the other hand, if a determination result can be obtained, the discharge destination of the residual sheet can be controlled according to the determination result. An example of the operations carried out in this case is described with reference to the flowchart in FIG. 7. In addition, identical operations shown in FIG. 5 and FIG. 7, as denoted by identical reference numbers, are not described in FIG. 7 repeatedly. If the detection sensor outputs an ON signal in ACT102 (YES in ACT102), the control section 200 acquires the determination result from the memory 210 (ACT121) and determines whether or not the residual sheet is reusable according to the determination result (ACT122). The control section 200, after determining the residual sheet to be reusable (YES in ACT122), controls the motor 501 to discharge the residual sheet to the first tray 110 (ACT123). On the other hand, the control section 200, after determining the residual sheet to be not-reusable (NO in ACT122), controls the second branching component 126, the motor 501 and the third conveyance path 122 to discharge the residual sheet to the second tray 112 (ACT124). As the sheet is discharged to a regular tray through this operation, it is not needed to give a message about the residual sheets in ACT106.

Although the erasing apparatus 100 for erasing the image formed on a sheet is described above as an example, a dedicated discrimination apparatus is also applicable which is used to determine the size of a sheet or determine the reusability of a sheet and sort sheets. The discrimination apparatus is obtained by removing the erasing section 108 from the erasing apparatus 100. Further, the second conveyance path 120 and the first branching component may also be removed together with the erasing section 108. In the discrimination apparatus, during the process of a reusability determination, the sheet subjected to an erasing processing is held on the sheet feed tray 102 and subjected to either of or both of the aforementioned sorting processing and the prior sorting processing.

The present embodiment may also be applied to an image forming apparatus capable of sorting and discharging sheets.

In the description above, it is exemplified that the reading section 106 is arranged and the determination on the sheet reusability is carried out based on the image read by the reading section 106, however, in a case of distributing sheets to trays according to sizes thereof, the reading section 106 may be replaced by a sensor such as the detection sensor 129 which outputs an ON or OFF signal according to the existence/absence of a sheet. In this case, the size of a sheet can be calculated based on the conveyance speed of a conveyance path and a time interval until the ON signal is output. Further, if a sensor, which irradiates a conveyed sheet with light from one side and receives the light from the other side to measure the quantity of light (light transmittance), is used instead of the reading section 106, the thickness of the sheet can be detected according to the quantity of the light received. And then the sheets are distributed to trays based on the determined sheet thickness. Further, in this case, the material (e.g. OHP sheet or ordinary sheet) can also be detected. It is described in this embodiment that the sheet distributing control is carried out based on required data relating to the sheet such as the residual recording color material left on the sheet, sheet size and sheet material and the like.

In embodiments described herein, a practical example is described in which the discharging roller 114 is arranged at the most downstream side of the first conveyance path 118 closest to the first tray 110, and a sheet is reversely conveyed to the position of the detection sensor by rotating the roller backward, however, the discharging roller may be any roller in the conveyance path.

In embodiments described herein, each conveyance path is stopped when the erasing apparatus is powered off or a fault such as sheet jam occurs, or when the cover is opened, and each conveyance path is recovered when the erasing apparatus is powered on or a fault such as sheet jam is cleared, or when the cover is closed.

As stated above in detail, by carrying out the control described herein, the residual sheet in an apparatus can be detected without leading to an increase in cost due to the increase of the number of sensors.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the invention. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention. 

What is claimed is:
 1. A sorting apparatus, comprising: a conveyance path configured to convey a sheet; a first storage section configured to store the sheet conveyed through the conveyance path; a detection section configured to detect whether or not the sheet conveyed in the conveyance path is in the detection target area of the conveyance path; a first roller configured at the downstream side of the detection target area of the detection section in a conveyance direction of the conveyance path to rotate to convey the sheet in the conveyance path towards the first storage section; and a control section configured to rotate, when the conveyance path is recovered from a stop state, the first roller in a direction reverse to the direction of the rotation mentioned above so that the sheet in the conveyance path is moved for a distance from the position of the first roller to the detection target area of the detection section.
 2. The sorting apparatus according to claim 1, further comprising: a cover configured to cover the inside of the sorting apparatus when closed and expose one part of the conveyance path outside the sorting apparatus when opened, wherein the control section further rotates the first roller to convey a sheet to the position exposed to the outside when the cover is opened.
 3. The sorting apparatus according to claim 2, further comprising: a notification section configured to notify the existence of a sheet in the sorting apparatus when the sheet held by the first roller reaches the exposed position.
 4. The sorting apparatus according to claim 1, further comprising: a second storage section configured to store the conveyed sheet; and a switching section configured to switch between the conveyance paths to store a conveyed sheet in either of the first and second conveyance sections, wherein the control section controls, in a case where a sheet held by the first roller is detected by the detection section, the switching section to convey the sheet to the predefined one of the first and second storage sections.
 5. The sorting apparatus according to claim 1, further comprising: an acquisition section configured to acquire the data relating to a sheet conveyed in the conveyance path; a second storage section configured to store the conveyed sheet; and a switching section configured to switch between the conveyance paths to store a conveyed sheet in either of the first and second conveyance sections, wherein the control section further controls, in a case where a sheet held by the first roller is detected by the detection section, the switching section to store the sheet in the either of the first and second storage sections according to the data acquired by the acquisition section.
 6. A detection method, including: reversely rotating, when a conveyance path is recovered from a stop state, a first roller so that a sheet in the conveyance path is moved for a distance from the first roller to a detection target area of a detection section. 